tbuckley/cabot-search huggingface dataset:
TMIC-81. INCREASED LEVEL OF IGFBP2 PROMOTES TUMOR METASTASIS IN SHH MEDULLOBLASTOMA
Authors: Haritha Kunhiraman, Leon McSwain, Shubin Shahab, Anna Kenney
Journal: Neuro-Oncology (2022)

Abstract Medulloblastoma (MB) is the most common pediatric brain malignancy. MB comprises 5 major subgroups known as WNT, SHH p53wt, SHH p53mut, Group 3 and Group 4. Among the four MB subgroups SHH group is the most dominant molecular subgroup in infants and adults. These tumors are proposed to arise from cerebellar granule neuron precursors (CGNPs), whose developmental expansion requires SHH signaling from the neighboring Purkinje neurons. Previous reports suggest that SHH group features a unique tumor microenvironment compared with other MB groups. To better understand how SHH MB cells interact with Tumor Microenvironment, we performed cytokine array analysis of culture media from SHH group Patient Tumor cells, spontaneous SHH MB mouse tumor cells and SHH MB cell lines. Further, confirmed these results using ELISA, Western blot, and immunofluorescence from human SHH MB cell lines, Smo/A1 mouse tumor primary cells and PZp53Med cell lines. In continuation to the observation of IGFBP2 expression in various cell types in single cell analysis, we analyzed the presence of IGFBP2 in astrocytes using Smo/A1 mouse tumor Immunohistochemistry. Our data showed increased levels of IGFBP2 produced by SHH MB cell lines compared to others. We analyzed the role of IGFBP2 in SHH MB tumor growth and metastasis. IGFBP2 knock-down stable cell lines showed phenotypic changes including reduced cell proliferation, cell migration and EMT. Further western blot analysis of IGFBP2 KD cells showed reduced expression of EMT markers also reduced the activation of STAT3. Our preliminary in vitro data suggest IGFBP2 exerts it metastasis-promoting role in SHH MB by regulating the expression of EMT marker proteins and matrix remodeling proteins. Further functional studies suggest that in SHH MB, IGFBP2 may regulate a STAT3-mediated EMT program to metastasize. These findings provide a strong rationale for further pursuing how IGFBP2 promotes medulloblastoma tumor cell growth and migration in vivo.
TMIC-76. HUMANIN RELEASE FROM TUMOR ASSOCIATED MYELOID CELLS PROMOTES GLIOMA CHEMORESISTANCE
Authors: Jiying Cheng, Min Li, Charlotte Flüh, Michael Synowitz, Krishna Bhat, Veerakumar Balasubramaniyan, Roland Kaelin, Rainer Glass
Journal: Neuro-Oncology (2022)

Abstract Transcriptomic screens of brain tumor (glioblastoma; GBM) parenchymal cells indicated tumor supporting traits of the GBM microenvironment, but largely excluded mitochondrially enriched gene-sets. Here, we show that a mitochondrial transcript of GBM parenchymal cells contributes to therapy resistance. We inspected the non-coding transcriptome of human GBM associated myeloid cells (GAM) and observed an upregulation of the mitochondrial ribosomal subunit MT-RNR2, which contains an open reading frame for the signaling peptide humanin. Immunohistology disclosed that humanin was preponderant in GAM. In vitro assays with a range of human stem-like GBM cells (GSCs) revealed that nanomolar concentrations of humanin can drive tumor cell expansion and chemoresistance to temozolomide. A series of genetic, pharmacological and Western blotting experiments showed that extracellular humanin increased GSC viability via stimulation of the GP130/IL6ST receptor and MAPK (Erk) activation. Humanin responsiveness was subject to inter-individual heterogeneity and predominated in GSC with high expression levels of the IL6ST subunit. Mechanistically, humanin promoted the ATR-dependent DNA-repair machinery in GSCs via induction of the DNA-clamp component HUS1. A slice culture model containing human microglia and GSCs confirmed these observations. Humanin is absent from the mouse brain. Exogenous delivery of humanin into orthotopic GBM mouse models or over-expression specifically of a secreted humanin variant recapitulated the in vitro findings. Blockade of the trimeric interleukin receptor with the brain permeant, FDA-approved drug bazedoxifene blocked humanin-mediated chemoresistance in vitro and in vivo. Overall, we identified a clinically applicable compound together with a predictive marker to prevent chemoresistance in a human-specific GBM model.
MODL-28. DEVELOPING A STRATEGY FOR MODELING HIGH-GRADE GLIOMA IN GӦTTINGEN MINIPIGS
Authors: Muhibullah S Tora, Kecheng Lei, Purva P Nagarajan, David P Bray, Rima S Rindler, Stewart G Neill, Michelle Zhang, Pavlos Texakalidis, Andrey Krasnopeyev, Crystal Gergye, Raphael James, John N Oshinski, Thais Federici, Jeffrey N Bruce, Peter Canoll, Nicholas M Boulis
Journal: Neuro-Oncology (2022)

Abstract BACKGROUND The current literature does not describe a reproducible large animal model of intracranial high-grade glioma (HGG). Prior work has demonstrated the feasibility of inducing HGG de-novo in rodents by targeting specific oncogenic pathways. Here we report our approach to the production of supratentorial HGG in a series of minipigs through lentiviral gene transfer and subsequent initial characterization of a porcine glioma cell line. METHODS Four minipigs received injections into the subcortical white matter using a combination of lentiviral vectors expressing platelet-derived growth factor beta (PDGF-B), HRAS, and shRNA-p53. Animals underwent behavioral monitoring through porcine neurobehavioral scoring (PNS) and veterinary monitoring. Magnetic resonance imaging (MRI) was conducted at endpoint prior to necropsy. Post-mortem tissue biopsies underwent tissue culture and neuropathologic evaluation with hematoxylin and eosin (H&amp;E) staining, immunohistochemistry, and immunofluorescent staining. Data are presented using appropriate statistical tests where relevant and descriptive statistics. RESULTS Two pigs received 50ul injections and reached endpoint by the end of post-operative week 1 and 2. Two pigs received 25 ul injections and were asymptomatic until a pre-determined endpoint of 4 weeks. MRI scans at endpoint demonstrated contrast enhancing, mass forming lesions at the site of injection with evidence of hemorrhage and perilesional edema, consistent with high-grade glioma. On H&amp;E staining high-grade glioma growth was identified in 100% of animals. We observed immunopositivity for tumor markers GFAP, OLIG2, NG2, SOX2, and PDGFRA, as well as redox markers, and microenvironmental features consistent with high-grade glioma. Porcine glioma cell cultures were found to have significantly greater proliferative rate compared to control, and demonstrated GFAP, OLIG2, PDGFRA, and CD68 immunopositivity. CONCLUSIONS Lentiviral gene transfer represents a feasible strategy for glioma modeling in the Gӧttingen minipig. With our described methodology, we present a realistic strategy for reproducible modeling of intracranial glioma as a platform for preclinical neurosurgical development programs.
TMIC-42. LEVERAGING B CELL IMMUNITY TO PROMOTE IMMUNOTHERAPY IN GLIOBLASTOMA
Authors: David Hou, Brandyn Castro, Andrew Zolp, Mark Dapash, Victor Arrieta, Junfei Zhao, Peng Zhang, Aida Rashidi, Emma Burnham, Ronit Patel, Maciej Lesniak, Jason Miska, Catalina Lee-Chang
Journal: Neuro-Oncology (2022)

Abstract Immunotherapy has revolutionized cancer treatment but has yet to be translated into brain tumors. Studies in melanoma and sarcoma, amongst other models, have revealed the accumulation of germinal-center-like B cells as a key survival predictor post-PD1 blockade. We seek to leverage B cell immunity to enhance immunotherapy effectiveness in glioblastoma (GBM). In human GBM and murine glioma models, we found that B cells in the tumor microenvironment (TME) are activated, but the expression of co-inhibitory molecules such as CD32 and CD72 blocks downstream effector function. Transcriptomic analysis showed high expression of inhibitory TGFβ receptors on B cells and high levels of TGFβ1 cytokine in the TME. We showed direct inhibition of B cell function through TGFβ signaling that could be prevented with TGFβ receptor blockade. Spatial multiplex immunofluorescence analysis of the TME revealed that tumor and myeloid cells express high levels of TGFβ and are also near B cells, allowing for TGFβ-mediated B cell inhibition. Blocking the TGFβ pathway via transgenic mice with TGFβ receptor knockout on B cells or TGFβ cytokine knockouts in myeloid cells, or generation of a CT2A tumor line with TGFβ cytokine knockdown, all demonstrated a survival benefit and more germinal-center-like B cells. There was also increased T cell proliferation and anti-tumor cytotoxicity. Finally, inhibiting αVβ8 integrin, a required factor that releases active TGFβ, is a translatable approach that also increased B cell proliferation and animal survival. Dual treatment with αVβ8+PD1 blockade showed the most potent survival as well as immunological memory against tumor re-challenge. Analysis of the B and T cell compartments after dual treatment showed synergy, with robust cellular proliferation and functional differentiation of plasmablasts and effector T cells. Collectively, our study highlights the importance of B cells in the TME and a remodeled approach to boost the effects of immunotherapy against GBM.
CNSC-14. ROLE OF A COLLAGEN RECEPTOR, LAIR-1, IN GLIOMA CELLS: A POTENTIAL THERAPEUTIC TARGET
Authors: Maria Luisa Varela, Andrea Comba, Mohammad Faisal Syed, Bhuvna R Murthy, Marcus N Barissi, Maria Castro, Pedro Lowenstein
Journal: Neuro-Oncology (2022)

Abstract Most primary brain tumors are gliomas, among which Glioblastoma multiforme (GBM) is the most common malignant brain tumor in adults. GBM has a median survival of 15-18 months, and despite extensive research remains incurable. Previous work in our lab has shown the importance of Collagen I, expressed by glioma cells, in glioma growth. Employing genetically engineered mouse models (GEMM) of glioma, NPA (NRas, shP53, shATRX), we identified that Collagen 1α1 (Col1A1) plays a key role in tumor malignancy. Molecular ablation of Col1A1 extends median survival, with a reduction in migration and proliferation. However, the mechanisms underlining these changes in survival, and the receptors mediating these effects remain unknown. Several collagen receptors are present in glioma cells. LAIR-1 is a collagen receptor that was originally described as an inhibitory receptor in hematopoietic cells. Since then, it has been demonstrated that LAIR-1 plays critical roles in the immune imbalance of autoimmune diseases and cancers. There have been several studies postulating the expression of LAIR-1 in tumor cells, including non-hematopoietic tumors. These studies suggest that LAIR-1 may constitute a novel receptor that tumor cells exploit to promote tumor growth and achieve immune evasion, yet its role in glioma remains unclear. Here we describe that glioma cells express LAIR-1, and that its molecular ablation in vitro showed reduced cell proliferation. In addition, GEMM lacking LAIR-1 (NRas, shP53, shATRX, shLAIR-1) exhibit improved median survival. Our preliminary data suggest that LAIR-1 expressed in glioma cells has a role in glioma aggressiveness. Currently we are further characterizing the role of LAIR-1 in high grade gliomas, as well as its potential as a therapeutic target. We hypothesize that blocking the interaction between LAIR-1 and collagen in the tumor microenvironment may improve median survival by reducing tumor proliferation.
TMIC-84. MULTIREGIONAL ANALYSIS OF GLIOBLASTOMA REVEALS TOPOLOGICAL DIVERGENCE OF CANCER CELLS AND THEIR SURROUNDING MICROENVIRONMENT
Authors: Roberto Salatino, Ugoma Onubogu, Florian Klemm, Johanna Joyce, Oszkar Szentirmai, Michalina Janiszewska
Journal: Neuro-Oncology (2022)

Abstract Tissue organization plays an important role in tumor development and evolution. Systematic investigation of the differences in the local composition of the tumor microenvironment (TME) in glioblastoma (GBM) in distinct regions of the tumor is needed for identification of traits driving tumor recurrence. Thus, we performed an analysis of three tumors, six spatially distant biopsies each, representing tumor surface, core, and deep margin. GBM cell fluorescence generated by the 5-aminolevulinic acid (5-ALA) metabolic labeling prior to surgery allowed us to enrich for the tumor cell fractions and the cells of the microenvironment, respectively, from each biopsy. Using RNA-seq and scRNA-seq we compared the transcriptomic profiles of GBM and tumor microenvironment (TME) at distinct locations within the tumor. We observed a gradient of GBM subtypes across the tumor regions, with a molecular identity progressively less defined from the tumor core towards the margins. Interestingly, the single-cell based copy number analysis revealed a subset of GBM cells that appeared to evade the 5-ALA labelling. The high prevalence of these 5-ALA-negative GBM cells within the deep tumor margins points to a metabolically distinct subpopulation that could be responsible for local tumor recurrence. The phenotypic gradient of cancer cells from tumor core towards the margins was also mirrored by tumor microenvironment-enriched fractions. Deep margin samples from the profiled tumors were transcriptionally more divergent than biopsies from other regions. Moreover, they were depleted from major populations of TME cells. In situ analysis revealed that TERT promoter mutant cells are not equally distributed across the tumor indicating the coexistence of GBM sub-clones with distinct evolutionary potential. Altogether, our results provide a novel insight into co-evolution of tumor microenvironment and GBM clonal heterogeneity within the context of the tumor tissue.
EPCO-46. EPIGENETIC STEMNESS PREDICTION ACROSS CENTRAL NERVOUS SYSTEM TUMORS MOLECULAR SUBTYPES
Authors: Tathiane Malta, Renan Simões, Maycon Marção
Journal: Neuro-Oncology (2022)

Abstract Tumor progression and therapeutic resistance in cancer have been strongly associated with stemness. Rather than focus on a discrete subpopulation for stemness and tumor maintenance, we might explore stemness as a continuous variable through machine learning algorithms. We chose One Class Logistic Regression algorithm to define an epigenetic signature to assess stemness in brain tumors using induced Neural Stem Cell (iNSC) through public DNA methylation data. In order to keep DNA methylation features most related to iNSC, we perform Wilcoxon test between 9 iNSC and 128 non-tumor brain tissue (methylation difference |0.3|, FDR &amp;lt; 0.01) and mapped the resultant features to genome regions. Our model revealed a positive correlation (r2 = 0.86 p &amp;lt; 0.001) with the pluripotent model from Malta et al. (2018) applied on TCGA gliomas. More remarkable, the iNSC model stratified IDHwt glioma survival by the median of stemness both on TCGA and GLASS cohorts (TCGA: p &amp;lt; 0.001, GLASS: p = 0.086; Likelihood ratio test). Having shown its potential, we next applied the iNSC model in other Central Nervous System (CNS) tumors using cohorts studied by Capper et al. (2016). The iNSC model stratified distinct DNA methylation-based subtypes, such as: i) ependymoma-RELA presented a very distinct and lowest stemness among all ependymal subtypes; ii) low stemness in lymphoma and high stemness in plasmacytoma; iii) low stemness pituitary-ACTH and high stemness pituitary-STH-DNS-B. Interestingly, gliomas IDHmutant have the lowest stemness. Additionally, among putative new entities identified by Capper, our iNSC model stratified high-grade-neuroepithelial-BCOR with the lowest stemness among embryonal tumors and infantile-hemispheric-glioma, high-grade-neuroepithelial-MN1, and anaplastic-pilocytic-astrocytoma showing differences among each other in “Other glioma” group. Our results indicate prognosis prediction for gliomas and recapitulate CNS tumors subgroups, which might suggest the iNSC model as a surrogate strategy to explore the stemness in brain tumors from an epigenetic perspective.
TMIC-13. GLIOMA-DRIVEN DENDRITIC CELL DYSFUNCTION AS AN IMMUNE EVASION STRATEGY AGAINST ADOPTIVE CELLULAR THERAPY
Authors: Dan Jin, Bayli DiVita Dean, Connor Francis, Laura Falceto Font, Alexandra Reid, John Figg, Mathew Sebastian, Catherine Flores
Journal: Neuro-Oncology (2022)

Abstract BACKGROUND Our previous studies has developed an adoptive cellular therapy (ACT) against high grade gliomas in both human and murine systems. ACT significantly improves survival in murine models of CNS malignancies. Our studies have shown that efficacy is associated with the observed increase in tumor-associated dendritic cells (DC) which arise from transferred hematopoietic stem cells (HSC). HSC-derived DCs play a pivotal role in mounting the anti-tumor immune response. In this study, we have identified that treatment resistance may be due to glioma-driven dendritic cell dysfunction. We observed significant down regulation of co-stimulatory markers on tumor-associated dendritic cells in mice that escaped ACT and subsequent capacity to activate tumor-reactive T cells.Method: KR158B bearing mice received HSC and tumor reactive T cells one day before 9 Gy irradiation followed by 3 does of BMDC vaccine. Tumor associated DCs were sorted from tumors evaded from ACT and co-cultured with primary KR158B reactive T cells or escaped KR158B reactive T cells. T cell proliferation and interferon gamma were detected for comparison. PCR array was performed to identify dysregulated functional genes.Results and CONCLUSIONS Functional evidence demonstrated that dendritic cells from resistant tumor had significantly decreased capacity in activating tumor-reactive T cells against either primary KR158B glioma cells or T cells generated to target tumor cells that evaded ACT. Gene expression data showed this may be due to significant decreases in genes associated with co-stimulation, T cell engagement, and antigen presentation.
IMMU-12. ABERRANT EGFR SIGNALING IS ASSOCIATED WITH DIMINISHED CYTOTOXIC T-CELL INFILTRATION IN GLIOBLASTOMA PATIENTS
Authors: Marissa Pioso, Lu Sun, Nicholas Bayley, Amanda Anil, Alexander Lee, David Nathanson, Robert Prins
Journal: Neuro-Oncology (2022)

Abstract Glioblastoma (GBM) has not benefitted from recent advances in immunotherapy compared to other solid malignancies, which suggests that a deeper understanding of the immunobiology of GBM is necessary to develop better therapeutic options. Both oncogenic signaling and evasion of immune destruction are hallmarks of cancer, contributing to tumor growth and reduced survival, respectively. Despite recent evidence in non-CNS malignancies demonstrating the importance of aberrant oncogenic signaling on shaping the tumor immune microenvironment, the impact of aberrant epidermal growth factor (EGFR) signaling – genetically altered in 60% of GBM patients - on the tumor immune microenvironment is not well characterized in GBM. To evaluate the importance of altered EGFR signaling in GBM patient samples, we performed single-cell transcriptomic analysis of primary tumor infiltrating leukocytes (TILs) from twenty-five patients which revealed aberrant EGFR signaling is associated with a unique tumor immune microenvironment in both primary and recurrent disease. Specifically, in the primary disease setting, higher infiltration of macrophages and dendritic cells, and significantly lower infiltration of T-regulatory cells was observed in EGFR altered patients compared to non-altered patients. In recurrent disease, EGFR alterations were associated with significantly diminished infiltration of activated and activated exhausted cytotoxic T-cells compared to unaltered disease. Intriguingly, differential gene expression analysis revealed that EGFR altered patients display significantly increased expression of interferon stimulated genes (ISGs) in both myeloid and lymphoid lineages, while analysis of the tumor compartment unexpectedly revealed greater expression of MHCI genes. Collectively, these data emphasize the impact of aberrant EGFR signaling on the tumor immune microenvironment composition and suggest further characterization of EGFR-immune crosstalk and mechanism is warranted in GBM.
QLTI-14. PEDIATRIC CENTRAL NERVOUS SYSTEM TUMOR SURVIVOR AND CAREGIVER EXPERIENCES WITH MULTIDISCIPLINARY TELEMEDICINE
Authors: Chantel Cacciotti, Isaac Chua, Jennifer Cuadra, Nicole Ullrich, Tabitha Cooney
Journal: Neuro-Oncology (2022)

Abstract Central nervous system (CNS) tumors are the second most common pediatric cancer; survivors develop chronic medical conditions and complex care needs. While telemedicine is accelerating, its effectiveness has not been assessed in pediatric CNS tumor survivors. We evaluated the experiences of those seen through our Pediatric Neuro-Oncology Survivorship Clinic at Dana-Farber/ Boston Children’s Cancer and Blood Disorder Center. Patients and caregivers who had a multi-disciplinary telemedicine survivorship appointment from January 2021 through March 2022 were invited to participate in an anonymous survey which included questions on demographics, travel, equipment, experiences with telehealth, and preferences for telehealth utilization. Thirty-three adult survivors and 41 caregivers participated in the study (45% response rate). The majority of respondents agreed or strongly agreed that telemedicine visits started on time (97%, Nf65), scheduling was convenient (97%, Nf59), clinicians explained things in an easy-to-understand way (97%, Nf59), listened carefully and addressed concerns (93%, Nf56), and spent enough time with them (95%, Nf56). However, only 58% (Nf35) of respondents agreed or strongly agreed they would like to continue with telemedicine and only 48% (Nf32) agreed telemedicine was as effective as office visits. In our univariable analysis, the majority of respondents reported telemedicine as better with regards to travel time (82%, Nf60), convenience (68%, Nf50), wait time (70%, Nf50), and ease of scheduling (56%, Nf40), while the majority reported office visits as better with regards to personal connection (58%, Nf41). Survivors were more likely than caregivers to prefer office visits for personal connection (72% vs 46%, p=0.027). The most common telemedicine difficulties were using the system (15%, Nf11) and asking questions they would normally ask in clinic (19%, Nf14). While multi-disciplinary telehealth may improve care efficiency and accessibility for pediatric CNS tumor survivors, initiatives to improve personal connection are necessary to optimize patient satisfaction.